The following disclosure generally relates to electrical circuits and signal processing.
Conventional amplifiers receive an input voltage VIN and produce an output voltage VOUT according to a gain AV, wherein the gain AV is defined as a ratio of the output voltage VOUT to the input voltage VIN. A variable gain amplifier permits changes in gain AV so as to adjust a signal level in the output signal.
Various conventional techniques can be used to control a gain AV of a variable gain amplifier. One type of gain control leverages an exponential property of a transistor (e.g., a bipolar junction transistor) to make exponential changes in gain AV. However, transistors are generally sensitive to conditions such as temperature, supply voltage fluctuations, and fabrication process variations. Consequentially, such adverse conditions can introduce errors into an application requiring an accurate output voltage VOUT.